A field of steel making has developed in which there is a demand for ultra-low carbon steel of 0.01% carbon or less. Conventional molten metal samplers have too many contaminants to be useful for sampling the melts during the steel making process to determine the composition of the melt. We have discovered various sources of carbon contamination that can affect and distort the lab analysis. Conventional samplers of the type shown in U.S. Pat. Nos. 3,791,219 and 4,069,715 are effective in other than ultra-low carbon melts. However, samplers of this type are not adequate to provide the desired accuracy free of distortion in ultra-low carbon steel melts.